Various textiles used in the clothing, furnishings and industrial fabrics industries are fire-unstable, i.e., they burn or melt or otherwise heat-degrade when in contact with flame or heat. For example, woven, knitted, and non-woven constructions of cotton, viscose, rayon, synthetics such as polyester, natural/synthetic blends and wool may burn or melt in the presence of flame or heat.
The application of flame retardant treatments to textiles, nonwovens, papers, and the like, is well known. Flame retardant fabrics may be treated in such a way that they do not ignite, or support combustion, or they may be treated to provide “flame blocking” properties. Flame blocking materials not only do not support combustion, but also can function to protect objects that are flammable or that can be damaged by fire.
Flame blocking materials can have many forms. For example, flame blocking materials may be composed of non-combustible materials like asbestos, glass, metal, or may be composed of organic materials like para-aramid, melamine, polybenzimidazole, or other materials that have resistance to flame and heat, or may be composed of combustible materials that are treated chemically to resist fire and heat. An intumescent material will tend to char, swell, and form a barrier to flame, hot gases, and conductive heat transfer. Exemplary intumescent materials include, but are not limited to, melamine, pentaerythritol, fluorocarbon, graphite, bentonite, clay, phosphated or borated melamine, ammonium polyphosphate polyols and the like.
Intumescent coatings are described in Intumescent Coating Systems, Their Development and Chemistry by H. L. Vandersall, J. Fire & Flammability, Vol. 2 (April 1971), pp. 97-140, which is incorporated herein by reference in its entirety. The application of an intumescent material to textiles is usually carried out by conventional techniques, such as knife coating, roll coating, spray coating, calendering, transfer coating or screen printing.
U.S. Pat. No. 5,645,926 to Horrocks et al. describes a flexible fire and heat resistant material comprising an intimate mixture of organic intumescent filler and organic fibres adapted to char intensely within the temperature range of 200° C. to 500° C.
U.S. Pat. No. 4,923,729 to Porter et al. describes a method for increasing heat dissipation from the smolder or open flame site of an upholstered article by interposing a fire barrier material between the outer upholstery fabric and the filler or padding materials. The fire barrier material is formed by coating a fibrous substance, such as glass fibers, carbon fibers, and the like with a latex containing a finely divided heat conductive metal.
U.S. Pat. No. 5,830,319 to Landin describes a flexible fire barrier felt and a method of producing the fire barrier felt. The felt includes: at least about 10 weight percent (wt-%) of an organic polymeric binder; at least about 5 wt-% of organic fibers having pendant hydroxyl groups (preferably cellulosic fibers); and at least about 10 wt-% of a heat absorbing compound; wherein the felt contains at least about 0.3 wt-% of phosphorus, as provided by a phosphorus-containing compound.
U.S. Pat. No. 5,070,119 to Nugent, Jr et al. describes an intumescent curable composition which contains as a resinous binder a flexible polyepoxide resin. The intumescent curable composition is usually in the form of a thick material such as a mastic and is spray applied to a substrate.
U.S. Pat. No. 6,153,668 to Gestner et al. describes a method of making a fire barrier material comprising the steps of (a) providing components comprising at least about 25 wt-% binder, at least about 10 wt-% intumescent compound, and at least about 5 wt-% organic fibers comprising an organic material having pendant hydroxyl groups, based on a total dry weight of the fire barrier material; (b) combining the components to form a mixture; (c) foaming the mixture; (d) placing the foamed mixture onto a substrate; and (e) drying the foamed mixture for a time sufficient to form the fire barrier material, wherein the fire barrier material has a density ranging from greater than zero to about 0.35 g/cm3. Once the mixture has been formed into a foam-like material, it is placed or applied onto a substrate, for example, by casting, pouring, or spreading. Placing or applying the mixture onto a substrate can be accomplished by casting the mixture onto a substrate and then pressing it to a desired thickness by means of a platen press, or it can be poured or cast into a mold lined with a release liner.
U.S. Pat. No. 6,265,082 to Dunham et al. describes a fire retardant composition consisting of a cured film, wherein the film is formed from a film-forming composition comprising a curable resin and at least one fire retardant, the fire retardant being included in an amount from about 5 to about 95 percent by weight based on the weight of the cured film, and wherein, when the film is adhered to a flexible substrate, the film substantially does not alter the hand of the flexible substrate.
U.S. Pat. No. 4,806,185 to Porter et al. describes a method for increasing heat dissipation from the smolder or open flame site of an upholstered article. The upholstered article comprises an outer fabric that houses and contains filler materials such as padding. The method involves interposing a fire barrier material between the decorative outer upholstery fabric and the filler materials. The barrier material completely envelops the filler material and can be woven or nonwoven and is made of coated fibrous substances, such as glass fibers, carbon fibers, polyaramid, polybenzimidazole, polymeta-phenylene diamine isophthalate, and combinations thereof. The coating consists of a latex of enhanced thermal conductivity containing a finely divided heat conductive metal such as aluminum, copper, nickel, and mixtures thereof, with the proviso that the outer upholstered fabric has a porosity rating of less than 10 cubic feet of air per minute per square foot, measured at a pressure of one-half inch of water. The amount of heat conductive metal can vary from about 4 to 20%, and preferably about 8 to 10% by weight of the coating composition. The fire barrier fabric can also function as an effective fire barrier with for example, bedspreads, quilts or mattress ticking, and the like. The outer face fabric and the fire barrier fabric can be attached sequentially to a cushion or furniture frame. Alternatively, a prelaminated fabric consisting of the face fabric can be adhesively laminated to the fire barrier fabric. The fire barrier fabric can also be sewn to an outer face fabric.
U.S. Pat. No. 4,824,709 to Tschirch describes a textile product having a textile material and a backcoating comprised of a polymer matrix and inorganic smoke suppressant and/or flame retardant intumescent particles. The backcoating may also contain an inorganic filler that further enhances the flame retardancy and low smoke properties of the textile product. The methods of forming the textile product include mixing the smoke suppressant and/or flame retardant intumescent particles with the backcoating prior to its application to the textile material or the simultaneous spreading of the particles on the textile material with the polymer backcoating in order to form a layer of the particles directly adjacent to the textile material.
U.S. Pat. No. 4,216,261 to Dias describes a process for imparting an intumescent, water repellent, fire retardant finish that is applied by conventional coating techniques to one side of a fabric. The treated material is then dried at temperatures in the range 222° F. to 260° F.
U.S. Pat. No. 3,889,022 to Whittaker et al. describes a flame-retardant composite article having a core of one or more combustible materials, at least partly covered by a combination of one or more flexible intumescent char-forming materials, and one or more textile fibrous layers.
Expandable graphite is a particularly effective intumescent material. Graphite to be used as an intumescent material is conventionally treated with an acid (e.g., sulfuric, nitric, acetic acid, etc.) which permeates the layers of the graphite structure and causes the graphite to become expandable and form a thick insulative layer of carbon char when exposed to flame. When a substrate, such as a nonwoven, knit, or woven fabric, is coated with a layer of material containing expandable graphite, the coating will expand and form a thick char when exposed to fire, heat, hot gases, or molten materials, and effectively block the progress of a flame. Unfortunately, when fabrics having graphite-containing coatings are processed into composite upholstery articles (e.g., panels for use in mattress construction) via sewing and/or quilting, the graphite tends to stain the surfaces of the composite articles.
FIGS. 1A-1B illustrate a conventional composite upholstery panel 10 having a ticking layer 12, a layer of resilient cushioning material 14, and a backing layer 16 with a coating 18 of material containing expandable graphite. The ticking layer 12, cushioning material 14 and backing layer 16 are quilted together in a pattern via thread 20, Graphite particles from the coating 18 work their way through the cushioning material 14 and the ticking layer 12 for example, via a quilting needle, and stain the ticking layer surface 12a adjacent to the quilting thread 20, as illustrated. The staining is indicated generally as 22.
Graphite staining is particularly troublesome when upholstery panels have white and other light-colored outer layers (e.g., ticking layers). Unfortunately, light-colored ticking layers and covers are preferred in many upholstery industries including the bedding industry. As such, graphite is typically not used as an intumescent material in the bedding industry.
However, because graphite is an effective intumescent material, it would be desirable to be able to utilize graphite in the various upholstery industries where white and other light-colored fabrics are utilized.